Memory devices are widely used in electronic devices, such as digital cameras and personal audio players, for storing digital data. Many different types of memory are available, each using a different fundamental technology for storing data, and the memory may be volatile or non-volatile memory. Resistive random-access memory (RRAM), conductive-bridge random-access memory (CBRAM) and flash are examples of non-volatile memory.
Referring to FIG. 1, plural conventional waveforms 1, 2 are shown wherein waveform 1 indicates voltages applied to a gate of an access transistor to implement set and reset operations and waveform 2 indicates voltages across a memory cell to implement set and reset operations. More specifically, the pulses of waveforms 1, 2 at time t=0 implement a set operation, the pulses of waveforms 1, 2 at times t=1, 3, 5, and 7 implement a reset operation and the pulses of waveforms 1, 2 at times t=2, 4, 6, and 8 implement a verify operation.
In some instances, a memory cell may fail to place in the reset state following the application of an original reset pulse (e.g., time t=1) as determined by a respective subsequent verification operation. In such a situation, subsequent reset pulses may be applied to the memory cells having the same current as the original reset pulse until the memory cell places in the reset state.
At least some embodiments are directed towards improved memory systems and memory programming methods as described further below.